Over the past few millennia we’ve remade our environment by altering ecosystems and modifying crops. We’ve changed how our children think through compulsory education. We’ve altered their immune systems with vaccines and antibiotics. But should we genetically modify our children? This is the central question of my new book.
We’ve always selected mates in a way that indirectly affects our children’s characteristics. But new forms of biomedical technology will soon enable parents to exercise more direct control over their children’s traits. Pre-implantation genetic testing (PGT) allows us to screen and select embryos for certain traits, including a reduced risk of developing diseases like cancer, cystic fibrosis and sickle cell anaemia. So far, this technology is limited by the still young science of genetics, and the small number of eggs women can generate through induced ovulation. But this is rapidly changing.
Machine learning (a form of weak artificial intelligence) is accelerating our understanding of what genes do and how they interact to shape traits. In addition, a new technique will allow us to take any somatic cell—including a blood or skin cell—and turn it into a pluripotent stem cell, from which we can create sperm and eggs. As this technology becomes cheaper, it will allow parents to generate a large number of embryos and choose which ones to implant.
Companies like Genomic Prediction already promise to allow parents to scan embryos not only for simple genetic disorders, but for polygenic traits that involve many genes interacting with one another in ways that make a trait or a disease more likely to materialize. Gene editing techniques like CRISPR Cas-9 and CRISPR Prime could, in principle, alter genes that affect health, height, personality or intelligence. We don’t necessarily know which genes these are yet, but that is a technical problem that genomics will help solve.
The first genetically altered babies were born in China in 2018, using techniques developed in the United States and Europe. The specific gene that was edited in these Chinese children silences the expression of a protein called CCR5, so that the person becomes immune to HIV. While CRISPR is routinely used in genetics labs around the world for research, this use of CRISPR to edit embryos was widely condemned because—for now—we don’t know the full effects of the CCR5 gene, and CRISPR itself can produce off-target mutations, which adversely affect the developing embryo and the child it becomes.
While I think gene editing will become more accurate, and our understanding of genetics will increase the temptation to edit human embryos, the controversy over CRISPR is beside the point. Even if no babies are edited in the future—which I doubt—embryo selection using IVF + PGT will become increasingly powerful and, some think, widespread. As more people use it to select for traits that predict success, more parents will find the cost of opting out too high to bear. They will begin to see the natural lottery as a worse bet than an artificial lottery in which a bunch of embryos are scanned and assessed for the likelihood that they’ll develop traits related to health, intelligence and empathy.
Are Genetic Interventions Morally Different from Environmental Ones?
Imagine you could spend a lot of time and money to get your children into an elite university like Princeton or Yale. Some parents do this by donating to the university, and others through outright cheating. But most students at these universities got there because they have high levels of heritable traits like intelligence and self-control, and because they were lucky enough to have a stable home life in a decent community. While higher education is coming under increasing scrutiny—its value surely depends on what subject we study, and how we spend our time at university—parents go to great lengths to make formal education accessible to their children.
Such parents probably don’t think that going to Princeton always results in success, wealth or happiness. They think it will make it more likely that their children will thrive over the long run. Many people drop out of universities because they get sick or don’t respond well to pressure, because they feel it’s a waste of time or because they aren’t smart or motivated enough to keep up with their peers. But those who make it through elite universities and choose challenging majors and enriching extracurricular activities end up with opportunities and friends that would be hard to find if they stayed in their hometown.
Most parents also vaccinate their children, try to feed them healthy food and insist on finding the best physicians for them when they get sick. All this is supposed to increase the chances that the child will thrive and grow up to be a happy, successful, productive person. Parents know they can’t guarantee these outcomes. They just do their best.
Yet, despite the fact that genes powerfully influence important life outcomes, many parents consider the prospect of genetically altering their children creepy. Some think it’s wrong to take on this much responsibility. As a character in Bernard Shaw’s Man and Superman puts it, “freedom means responsibility: that is why most men dread it.” But parenthood is the ultimate responsibility. While parents should exhibit humility—as Michael Sandel argues in “The Case Against Perfection,”—it seems like an abdication of responsibility to ignore genetic risks. Knowing that my wife and I are both carriers of a genetic variant that substantially increases the risk that our children will have Tay Sachs disease might lead us to test a fertilized egg for the disease before implanting it (or, in an extreme case, to marry someone else).
Some parents worry that selecting for traits could have unforeseen consequences. But environmental interventions also have unforeseen consequences. New medications and nutrition fads can produce harm rather than health. And sometimes the school we choose ends up indoctrinating rather than educating our kids.
Since we can only change the chances that our children will thrive by altering their environment, why not also use the available data to influence the genetic basis of their physical and psychological traits? This is not an argument for trying to radically reshape our children before there is a scientific consensus about this genetic basis. But, as some prominent philosophers argue, editing or selecting embryos isn’t morally different from altering the environments of our children. It’s just a lot more uncertain—for now.
Genetic Enhancement and Collective Action
Assume that, within a few decades, we know enough about genetic interactions to significantly shape our children’s traits though embryo selection or gene editing, without undue risks to their health. What would we choose? Obviously, we’d want our children to be free from mutations known to cause serious diseases. If the evidence of how women select sperm donors is reliable, many would probably also select for traits like intelligence and kindness—at least up to a point. Intelligence is correlated with a host of important life outcomes, in areas ranging from income and criminal tendencies to marriage stability and mortality. And the kind of empathy that underlies kindness gives ordinary people—but not psychopaths, who lack empathy—the ability to form valuable relationships like friendship and love.
However, what happens when parents select in a way that increases the welfare of their child, but has collectively detrimental effects? Economists call situations like this collective action problems: situations in which each person selecting the course of action that is best for him- or herself produces an outcome that is bad for everyone.
We can imagine parents selecting for traits that benefit their child but that make the population as a whole worse off. The simplest example is an imbalanced sex ratio. In pre-industrialized countries where physical labour commands higher wages, boys might be preferred to girls. And, in developed countries, where patience carries a premium, girls might be preferred to boys. Even a slight difference in the average preferences of parents could lead to something like a 60/40 sex ratio imbalance. While there are reasons to doubt this will happen, including the fact that poorer countries might lack the technology to select or alter embryos for some time, it’s an obvious example of a collective action problem involving genetic selection.
A more interesting example is how we might sculpt our children’s innate immune systems. Each of us might be tempted to select for (or edit) genetic variants that produce immunity to a local microbe, but the population as a whole might be better off with more immuno-diversity because microbes constantly evolve. As the Irish Potato Famine illustrates, monocultures can be dangerous in both agriculture and people.
Parents might also select for positional goods, where everyone wants more than the average amount of a trait because having it confers social advantages. Women are attracted to men who are at least a little taller than average, and this could push parents to enhance height in boys to the point at which it stresses the cardiovascular system. Each would be better off increasing their son’s relative attractiveness in this way, but future populations would be worse off because of the collective consequences.
Sometimes the pursuit of positional goods can bring social benefits. Competitions in sports and music are won by some and lost by others. But if the pursuit of positional goods in these domains produces better sports and music, and smarter doctors and researchers, humanity is better off. Similarly, if enhancing general cognitive ability produces not only more inventions from which we all benefit, but more cooperation as a side effect, choosing to cognitively enhance our children is a public good, rather than a collective action problem. At least up to a point.
Pursuing positional goods that produce net costs rather than net benefits is one kind of collective action problem. But there are many others. Perhaps a certain amount of cognitive diversity is desirable because it helps groups of people learn lessons that wouldn’t be as obvious if everyone in the group had a similar cognitive style.
Now suppose it is discovered that genes that predict creativity also carry a slightly higher risk of depression, autism and schizophrenia (there is evidence that this is the case). Parents who have perfectly good reasons to select against these conditions could reduce creativity in the population as a side effect. This could be good for each person, but bad for everyone as a whole. While some parents would select for creativity even with these risks, because they think there is more to life than subjective well-being, a variety of collective action problems might result from the freedom to select or alter embryos.
Where Do We Go From Here?
The first reaction many people have towards novel technologies that can remake the human population is to ban them. While I don’t share this impulse, it is a perfectly reasonable reaction at the current time to gene editing techniques that can cause serious side effects, such as off-target mutations. Nevertheless, it is worth stressing the dangers not only of allowing access to genetic enhancement technologies, but of banning it.
Outlawing markets for goods when demand is high tends to create black markets. We all know what happens when governments attempt to stamp out markets for recreational drugs. When laws against buying and selling these goods are enforced with harsh penalties, demand for them can be reduced. But it never goes away, and it often goes underground and abroad. I suspect this is what would happen with genetic enhancement technologies. If even a single country—perhaps China—permits or even subsidizes the use of new genetic technologies, many people around the world who can afford to pay the price to access them are likely to do so.
Prohibitive laws tend to make accessing goods and services more expensive, which rewards the wealthy and well-connected—the very people who are already likely to possess both genetic and social advantages. Many people worry about increasing economic inequality. Yet they often fail to recognize the role of genetics in producing inequality across generations. This is due in part to the fact that people with similar abilities tend to select each other as mates. Now imagine the social consequences of creating a system in which only the smartest and richest can afford to access genetic enhancements for themselves or their children through medical tourism or black markets. Inequalities will not go away if we allow access to genetic enhancement technologies. State of the art techniques will always be expensive to access. But prohibiting access can make inequalities worse rather than better.
Look at the global market for kidney sales. Because kidney sales are prohibited in developed countries, rich citizens of developed countries travel to India to purchase kidneys on the black market, ignoring prohibitive laws in order to save their lives.
The promise of new reproductive technologies is clear. But the collective action problems they might create are worth paying attention to. In the next few generations, it is likely that, one way or another, humanity will transform itself.
Some parents will presumably decline genetic counseling, ignore technology and have children the old-fashioned way. People might even eventually become so different from one another that political separation between the enhanced and un-enhanced will occur. Freedom has a price. But freedom also permits us to understand ourselves, and to transform our descendants into the kinds of creatures we want them to become.